Hybrid Fem-T-Matrix Technique for the Analysis of Acoustic Wave Scattering by Elastic Shells of Revolution.

摘要

A hybrid finite element cum T-matrix technique is introduced for the analysis of problems involving acoustic wave scattering by shells of revolution immersed in water. The concept of a mechanical impedance or receptance is used from the theory of vibrations to provide a relationship between the velocity of the shell surface and the pressure acting upon it. This relationship is introduced in the Helmholtz integral relations for the incident and scattered fields and a T-matrix for the scattering problem is derived. The mechanical impedance is calcuated by a conventional FEM technique. Numerical results are obtained for spherical shells as a check on the numerical procedure and also for a finite capped cyclindrical shell for waves incident along the rotational axes of symmetry. The comparison with the experimental results of Dr. S. Numrich and Dr. L. Dragonette of the Naval Research Laboratory is excellent. (Author)